Liquid stains are the prevalent means for coloring wood and wood veneer in the production of furniture or other wooden decorative products. In the furniture industry where much of the staining and other finishing is done by hand on an assembly line basis, problems have been created in staining difficult to reach areas or those areas comprising more than one kind of wood or the appearance of such. The pieces generally are moving through the production line too quickly to be properly stained if the process requires special attention. The obvious solution in most instances is to slow production which results in increased costs ultimately borne by the consumer.
A similar problem also existed in the specialty products area where, in addition to staining, other steps such as embossing and/or applying a different stain to selected areas of a piece were involved. Prior art methods generally included treating each step separately; i.e. dye cutting the overlay, embossing and/or staining the overlay, application to the furniture, taping the overlay, then staining and finishing the other portion of the piece. In many large suites of furniture such a multi-stage process is prohibitively expensive and the suite is generally removed from the line.
Additionally, there are frequent attempts to stain or color one wood to appear as another. This is usually done when it is economically desirable to utilize less expensive species such as hard rock maple or print grade maple veneer by staining them to give the appearance of cherry, mahogany or other more expensive varieties. On other occasions, it may simply be desired to achieve an unusual or unique color combination by staining and/or embossing some portions of the same piece of furniture differently for decorative purposes only.
For example, to produce a wood inlay appearance according to the prior art methods, it is necessary to dye cut the various types and pieces of wood and wood veneers to be inlaid. At that point, in order to achieve a cherry effect, a layer of cherry veneer would be laminated onto a cheaper variety of wood. Then the piece would be sent to the embosser for texturing. Following the embossing step the furniture piece is forwarded to the finishing line for hand staining and finishing. If a portion of the inlay is to be stained a cherry color, and a second portion another color great care involving taping over the portion not to be stained must be taken that the different stains do not overlap or bleed into the adjoining inlay. Therefore, a piece of furniture moving along an assembly line at approximately twenty feet per minute cannot be so precisely stained.
As stated above, if attempted at all, achieving all these effects usually involves an expensive and time consuming individual staining and finishing process. Not only are the known processes usually multi-stage, but the inventory of stains and finishing materials is large and represents a sizeable outlay of funds.
With the development of the present invention however, many of the above problems have been eliminated. The unique wood coloring process broadly includes the steps of applying a non-alkaline chemical coloring mixture to a piece of wood preparatory to or simultaneously with the embossing process. The heat and pressure applied during the embossing operation then causes the area under pressure to be colored while the other area remains uncolored. Thus the separate staining procedure and the necessity of using a variety of woods is eliminated. It has been found that the new process allows the very economical production of decorative, colored inlay appearance on mass produced furniture; an achievement previously considered too expensive and difficult to be utilized in mass production operations.
As will be described in greater detail hereinbelow, the new process combines the steps of staining or coloring the wood and embossing if embossing is required. Obviously if embossing is not desired the heated pressure rolls, or plates may be smooth and free of any intaglio design. The non-alkaline chemical coloring mixture is spread directly on the wood and then subjected to the heat and pressure of the embossing process. Thus, adjacent portions of wood not engaged by the heated rolls or plate may be left uncolored, or have applied thereto a different stain in a subsequent operation. The resulting effect is that of economically producing furniture pieces with the appearance of expensive wood inlays or mosaics. While the present technique has proven successful on the treatment of hard rock maple and print grade maple veneers, it is believed that the same technique could be utilized on other maples and even on other woods that have a significant sugar content.
The objects of the present invention include the economic production of furniture having the effect of expensive wood inlays, and the utilization of less expensive woods which can be treated or colored to give the appearance of more expensive varieties. A further advantage is that overall coloring of the wood may be better balanced and controlled. The chemical/sugar mixture utilizes and enhances the naturally occurring sugars in the wood so that inexpensive woods may have the effect and appearance of more expensive varieties.